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Archive for the ‘materials’ category: Page 10

Apr 4, 2024

A Counterintuitive Set of Tunneling Effects Observed at Last

Posted by in categories: energy, materials

Graphene is the setting for the first demonstration of relativistic electrons’ paradoxical ability to whiz through a barrier, provided the barrier is high enough.

If an electron in a material has a speed that is independent of its energy and if it encounters a barrier head on, it can tunnel straight through. Derived by theorist Oskar Klein in 1929, this counterintuitive finding remained little tested in the lab because it is hard to make electrons approach a barrier head on and to stop them scattering off the edges of the sample. Now Mirza Elahi of the University of Virginia and his collaborators have observed evidence of Klein tunneling in monolayer graphene. What’s more, they also observed the opposite effect, anti-Klein tunneling, in bilayer graphene. In anti-Klein tunneling, head-on electrons do not tunnel at all, while others approaching the barrier at an intermediate angle do [1].

Graphene’s hexagonal lattice can be thought of as two identical interpenetrating triangular sublattices. One consequence of that view is that graphene’s charge carriers—electrons that hop between the two sublattices—behave as if massless and relativistic at low energies. Another consequence is that the two sublattices bestow on the electrons a chiral property, pseudospin, that resembles spin, which controls the nature of the transmission across the barrier.

Apr 4, 2024

Unlocking exotic physics: Exploring graphene’s topological bands in super-moiré structures

Posted by in categories: materials, physics

In a new study, scientists from Singapore and Spain have presented a new avenue for exploring exotic physics in graphene. They focus on electronic interactions in graphene when it is sandwiched in a three-layer structure which provides a platform to exploit unique electronic band configurations.

Apr 4, 2024

Unlocking the Secrets of Strength Through 3D Crack Analysis

Posted by in categories: engineering, materials

The last time you dropped a favorite mug or sat on your glasses, you may have been too preoccupied to take much notice of the intricate pattern of cracks that appeared in the broken object. But capturing the formation of such patterns is the specialty of John Kolinski and his team at the Laboratory of Engineering Mechanics of Soft Interfaces (EMSI) in EPFL’s School of Engineering. They aim to understand how cracks propagate in brittle solids, which is essential for developing and testing safe and cost-effective composite materials for use in construction, sports, and aerospace engineering.

Apr 4, 2024

Electrically Tunable Metasurfaces: Liquid Crystal Alignment by Dielectric Meta-Atoms

Posted by in categories: materials, particle physics

Dielectric metasurfaces, known for their low loss and subwavelength scale, are revolutionizing optical systems by allowing multidimensional light modulation. Researchers have now innovated in this field by developing a liquid crystal-based dielectric metasurface that streamlines manufacturing and enhances device performance.

Dielectric metasurfaces represent one of the cutting-edge research and application directions in the current optical field. They not only possess the advantage of low loss but also enable the realization of device thicknesses at subwavelength scales. Moreover, they can freely modulate light in multiple dimensions such as amplitude, phase, and polarization. This capability, which traditional optics lacks, holds significant importance for the integration, miniaturization, and scaling of future optical systems. Consequently, dielectric metasurfaces have attracted increasing industrial attention.

In this study, Professor Daping Chu’s team at the University of Cambridge developed a novel liquid crystal-based tunable dielectric metasurface. By leveraging the dielectric metasurface’s inherent alignment effect on liquid crystals on top of its electrically controllable properties, the need for liquid crystal alignment layer materials and related processes is eliminated, thus saving device manufacturing time and costs. This has practical implications for devices such as liquid crystal on silicon (LCoS).

Apr 4, 2024

Ways Automation Can (And Will) Impact The Manufacturing Industry

Posted by in categories: materials, robotics/AI

Many of us have seen photos of and read stories about robots working on the production floor in factories, speeding up old-school assembly lines to build products more quickly. And while the robotics trend in manufacturing is continuing to grow, that’s not the only way technology (including artificial intelligence) and automation are impacting the industry.

From enhancing worker safety to more efficiently moving goods and materials from point A to point B, automation is making its mark on the manufacturing industry, and tech experts expect even more changes and improvements in the near future. Below, 17 members of Forbes Technology Council discuss specific manufacturing tasks that are (or soon will be) handled more efficiently, safely and productively by technology and automation.

Apr 3, 2024

Easy compression, easy flow: Research team designs new granular materials

Posted by in category: materials

When we take a stroll on the beach, we walk on the sand without any trouble. The sand appears solid and is difficult to compress. When we put the same sand grains in an hourglass, they behave very differently: the sand flows like a liquid.

Apr 3, 2024

Intel to Build Next-Generation Chips Using ‘Glass Substrate’

Posted by in categories: materials, robotics/AI

Year 2023 face_with_colon_three


The new manufacturing method deals with the packaging substrate, the material to which chip dies are bonded. Intel and others have long used plastic (also known as organic) substrates, but the material can shrink or warp during the chip-making process, leading to defects.

Continue reading “Intel to Build Next-Generation Chips Using ‘Glass Substrate’” »

Apr 2, 2024

Strong AI Is A Theoretical Impossibility

Posted by in categories: materials, robotics/AI

Thesis:

Part I: It has been proven that the human mind cannot be analogous to an electronic (or any other type of) computer, and the functioning of an intellective mind cannot be reproduced (though it can certainly be simulated) by any type of mechanical device, including modern artificial intelligence systems.

Part II: It is further impossible that the human mind is a purely material thing (including some “emergent property” of matter).

Apr 2, 2024

Supplementary_Material_MS_ADV21-AR-02206.pdf

Posted by in categories: augmented reality, materials

Estimation of the mass of all visible matter of thf universe.


Shared with Dropbox.

Apr 1, 2024

Metamaterials for Analog Optical Computing

Posted by in categories: computing, materials

Novel metamaterial-based architectures offer a promising platform for building mass-producible, reprogrammable schemes that perform computing tasks with light.

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